browser_passkey_create

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description must carry the full transparency burden. It discloses that private keys are omitted unless includePrivateKey=true, and that import requires all four key-material fields. However, it doesn't state whether the operation persists in the browser, whether it can overwrite an existing passkey, or any permission/security implications—significant gaps for a mutation tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, each with a distinct purpose: the primary action, the import condition, and the private key return behavior. No redundancy or filler; the generate/import distinction is front-loaded, and every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no annotations and no output schema, the description covers the key conditional (import vs. generate) and the private key return behavior. It doesn't explain what a generated passkey returns or whether the credential is persisted, but for a 6-param tool with one required param, the instructions are sufficient for basic correct invocation. Minor gaps around side effects and output prevent a 5.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description adds meaningful context by specifying that import requires all four key-material fields, a condition not inferable from the schema alone. It also restates the includePrivateKey behavior, which is already in the schema, but the import condition justifies a 4.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Generate or import') and resource ('a virtual passkey'), and it distinguishes two modes of operation. However, it does not explicitly differentiate itself from sibling tools like browser_passkey_install or browser_passkey_list; the name helps, but the description alone doesn't fully clarify when to use this over siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives a conditional for import mode ('provide all four key-material fields'), which implies when import is appropriate, but it doesn't explicitly state when to generate vs. import, nor does it mention alternative tools or when not to use this tool. Usage context is present but not fully developed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.